318 



loRTY-sixiH Report on the State Museum 



Lintner: in Count. Gent., Ivi, 1891, pp. 317, 374, 637; in Canad. Entomol., 



xxiii, 1891, i>. 230 (in Hudson river valley); in Science, xix, 1892, p. 



343; 8th Rept. Ins. N. Y., 1893, p. 219. 

 Riley-Howard : in Insect Life, iv, 1891, pp. 127-9 (description and habits from 



Loew), p. 225 (oocurrence in New York); id., v, 1893, p. 200 (is iindoubt- 



edly P. x>iiHcola of Foerster), pp. 226-230 (observations of Mr. Slinger- 



land, and dimorphism). 

 Powell : in Orange County Farmer, May 21, 1891 (I^rief notice). 

 Fisher : in New Engl. Homestead, Dec. 5, 1891; in Bull. No. 17, Hatch Agr. 



Exp. St., 1892, !>. 24 (habits and remedy). 

 LODEMAN : in Garden and Forest, v, 1892, p. 285 (brief notice of habits, etc.). 

 Sllngerland : in Count. Gent., Ivii, 1892, p. 629; in Canad. Entomol., xxiv, 



1892, p. 207 (injuries, broods, remedy): in Insect Life, v, 1892, pp. 



100-103 (description, transformations, remedies, etc.); Bull. 14, Cornell 



Univ. Agr. Exp. St., Oct., 1892, pp. 159-186, 7 figs. (fuU account). 

 Smith: in Canad. Entomol. , xxiv, 1892, p. 207 (copper and London purple 



spraying for it); Insect Life, vi, 1893, p. 192 (injuries and spread in 



New Jersey). 



Until within a few years the pear tree has been remarkably free from 

 insect attack — the amount of injury from such source being probably 

 less than five per cent of that to which the apple tree has been subjected. 

 Recently two pests have forced themselves upon the notice of pear- 

 growers, which have already inflicted serious losses, and threaten, unless 

 arrested, gi-eatly to interfere with the cultivation of this most excellent 

 and prized fruit. Of these, the pear laidigQ, Dij)losis pyrivora (noticed 

 in the })receding Report), which was introduced in this country about 

 the year 1880, has not become broadly distributed, and has not occa- 

 sioned much trouble except in western Connecticut and in portions of 

 the Hudson river valley. 



The pear-tree Psylla is also an introduced insect, which has been with 

 us for a number of years — hoM^ ^owg, is not known, 

 but long enough to have carried it into some of our 

 western States. It has, at times, multiplied exceed- 

 ingly in particular localities and become very 

 destructive, as notably in the summer of 1891, in 

 the Hudson river valle}-, in association with the 

 pear midge. Fortunatel}'^, however, after continuing 

 its injuries for a 

 few years, its ex- 

 cessive multipli- 

 cation seems to 

 operate as a check to its further 

 increase, and to consign it for 

 another term of years to insignifi- 

 cance in numbers and comparative 



, 1 Fig. 10.— Wings of the pear tree Psylla; c, 



narmlessneSS. clavus; c. s., claval suture; s, stigma. 



Fig. 9.— The pea'"-tree 

 Psylla, Psylla pyri- 

 coLA, male. 



